The exciting current work on the biochemical and genetic bases of the major affective disorders makes more salient the need to bridge the sciences and begin to develop concepts and markers linking the physical and neurological substrate with the complex behavioral manifestations of these disorders. A developmental framework provides a basis for moving beyond correlational assessment to causal modeling. The project will be a step in this process. A rich body of data on the children's birth complications, physical development, cognitive development and neurological development will be brought together as profiles for individual children. These profiles will be subjected to a cluster analysis. It is expected that some of the clusters of children will be associated with higher family loadings for affective illness. It is also expected that particular clusters will be associated with specific social, emotional, and/or cognitive outcomes, or with the development of symptoms of affective illness, and/or behavioral disorders in the children.